the many shapes of delay


About the different applications of audio delay effects.

There are quite a number of different types and applications for the audio delay effect in the audio production ranging from plain technical delay application up to all the musical and creative ranges of application. The rather technical or correctional delay typically is a plain digital delay which serves as a sample accurate alignment tool. Such alignments might be necessary for example for plug-in delay compensation (when a plug-in introduces latency) or during the mixing process to align a group of recorded tracks or samples. The so-called pre-delay can also be seen as an alignment sort of thing where the direct source signal has to be aligned in a positive or negative manner in relation to a processed signal, e.g. in a reverb effect. [Read more…]

I do believe in feedback

If I would have to state just one single universal principle which life as a whole rests upon then I would probably refer to the principle of feedback. But don’t worry, I don’t want to indulge in rather esoteric directions here but just move on a little bit towards basic system theory and how this relates to audio processing.


According to classical control theory, such systems are taking its output information and feeding it back in to the process input and that way closing the loop – hence the name closed loop system. In DSP audio land, the information is the audio signal itself and the audio (feedback) path constitutes the closed loop system. Audio signal processors such as feedback compressors or guitar amp effects are good examples for specific applications. While the control theory provides a lot of guidance for closed loop systems e.g. on handling differential equations and stability criteria, this can get pretty much nasty in practise because of the potential manifold of feedback loops in the circuit and not just only the main audio path. [Read more…]

NastyDLA – final teaser and release info

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NastyDLA – technical architecture

NastyDLA - technical architecture

simplified technical architecture

Internally, NastyDLA consists of quite a bunch of DSP processing building blocks which as a whole are summing up to an authentic signal path simulation of it’s analog models. The blocks and the according signal flow are shown in the diagram above. Basic signal flow goes from left to right except the feedback path which goes in the opposite direction.

With NastyDLA, signal path coloration already starts in the input stage which provides a complete model of both, frequency and phase response as well as dynamic saturation. It’s located in the dry path but all nonlinear processing and coloring can be disabled on demand so it remains as a simple input volume control then. But while switched in, the input stage can greatly contribute on getting the processed signal to fit right into a mix. [Read more…]

NastyDLA – some tape delay fun

To make up a complete and sustaining sequence out of  some melodic pattern is a standard task for the electronic musician. The good old tape delay is his best friend then, providing not only consistent and sustainable echos which are glueing nicely with the original signal but also offering some realtime modulation possibilities as well, to animate some maybe rather static sources.

In this short demo a static pattern is used and NastyDLA is going to be in charge as a tape delay replacement. The chorus is not used in this example but the plug-ins coloring possibilities are shown to some extend: After some bars the timbre of the delay feedback loop changes to a higher pitch and then to a lower one (and vice versa) while simultaneously the feedback amounts are going to change. To the end when the pattern stops, the “tape speed” is slowed down first and accelerated back again afterwards to demonstrate its artifact-free modulation capabilities.

Note how smooth the saturation behaves when driven into self oscillation w/o the usual amount of aliasing artifacts. The delay line generation in this example is set to “dual mono” mode (with 8th to the left and dotted 8th to the right) and the time modulations can be done separate per channel. All animations were done in realtime with host automation and in general all plug-in parameters can be automated in the host.

introducing NastyDLA

There are just a few audio effects available that are capable of instantly turning a small and wimpy riff into something big and meaningful. One of them is the classic chorus/echo combination. Beside the individual classic echo or chorus devices these combined devices were historically build around true tape or bucket brigade delays.

From today’s production standards perspective they might be easily overseen (feature wise) but on the other hand they are still pretty much demanded due to their specific and warm tone and this unique sound quality is probably the charm which still today attracts producers and audio engineers to use them in their actual music productions.

NastyDLA is going to follow this path and recreates all the specific tone qualities while adding just some few but well selected modern features. The plug-in implements some of the most distinctive and much appreciated sonic effects generated by these devices:

  • classic chorus and echo effects
  • authentic signal path coloration
  • tape-delay style feedback and saturation

NastyDLA applies gentle feedback driven delay effects, performs smooth audio signal modulations and adds extra harmonics and saturation effects. It will be available as a freeware VST plug-in for Win32 compatible systems later this autumn.

related links: the classic chorus echo device

from phase alignment to delay

In the recent article from phasing to phase alignment I had a closer look to what the Little Labs IBP actually does and hinted that in principle it could be easily extended to a plain but already musical sounding delay unit. And in fact, given the digital version, this could easily be done by some rather simple routing and addition: [Read more…]

compressor gain control principles

A short compendium on digital audio compression techniques.

Basic compressor configurations

Compression vs. limiting

Technically speaking the same principles are used in audio signal limiting and compression processors but just the transfer curves and envelope follower settings are different. Ultra fast attack rates and high ratio amounts are used for limiting purposes which causes just very few peaks to pass on a certain threshold.

In digital implementations limiting processors can be more strict due to look-ahead and clever gain prediction functions which guarantees that no peak information passes the threshold. That is called brickwall limiting then.

[Read more…]